A cyclodextrin (hereinafter referred to as "CD") is a cyclic dextrin composed of glucoses bonded to each other by an .alpha.-1,4 bond therebetween, and .alpha.-, .beta.- and .gamma.-CD each comprising 6, 7 and 8 glucoses, respectively, are well known. Recently, in order to elevate the solubility of CDs, branched CDs each having a glucosyl group or a maltosyl group bonded to CD via the .alpha.-1,6 bond have been produced.
Such CDs and branched CDs have cavities in the inside of the molecule and the inside of the cavities is lipophilic. Therefore, these CDs have an including capacity for forming inclusion (clathrate) compounds. taking various oily substances thereinto. As CDs and branched CDs have such properties, they are widely used in various fields of food industry, cosmetic industry and drug industry.
Recently, in the drug industry, in order to reduce the harmful side effects of drugs, a cell recognizing property of saccharides has been noticed and a study of utilizing CDs as a sensor to mark cells for a drug carrier in a drug delivery system has been effected actively. In particular, it is well known that galactose has a strong affinity with liver tissues and that mannose has an affinity with liver parenchymatous cells, liver non-parenchymatous cells and macrophages.
We the present inventors have already succeeded in development of a galactosyl-branched CD and a mannosyl-branched CD in which a galactosyl group or a mannosyl group, respectively, is bonded to the glucosyl group of the side chain of a branched cyclodextrin.
Under the situation, we tried to produce a galactosyl-CD and a mannosyl-CD in which a galactosyl group or a mannosyl group, respectively, is directly bonded to the CD ring by transglycosylation, for the purpose of applying both the including capacity of CDs and the above-mentioned characteristics of galactose and mannose to a drug delivery system. As a result, we have found that a commercial .alpha.-galactosidase is used for producing a galactosyl-CD in which a galactosyl group is bonded to the glucosyl group of an .alpha.-, .beta.- or .gamma.-CD via an .alpha.-bond by transgalactosylation from an .alpha.-galactosyl compound, that a commercial .beta.-galactosidase is used for producing a galactosyl-CD in which a galactosyl group is bonded to the glucosyl group of an .alpha.-, .beta.- or .gamma.-CD via a .beta.-bond by transgalactosylation, from a .beta.-galactosyl compound, and that a commercial .alpha.-mannosidase is used for producing a mannosyl-CD in which a mannosyl group is bonded to the glucosyl group of an .alpha.-, .beta.- or .gamma.-CD via an .alpha.-bond by transmannosylation, from an .alpha.-mannosyl compound. In particular, we have found that an .alpha.-galactosidase derived from green coffee beans is used for efficiently producing a galactosyl-CD in which one or two galactosyl groups are bonded to the glucosyl group of an .alpha.-, .beta.- or .gamma.-CD via an .alpha.-1,6 bond by transgalactosylation. In addition, we also have found that an .alpha.-mannosidase derived from jack beans is used for efficiently producing a mannosyl-CD in which one mannosyl group is bonded to the glucosyl group of an .alpha.-, .beta.- or .gamma.-CD via an .alpha.-1,6 bond by transmannosylation. On the basis of the finding, we have completed the present invention.